The present invention relates to abrasive sheets and methods of producing abrasive sheets. More particularly, the present invention relates to flexible abrasive sheets for withstanding heavy usage in the abrasion of materials. The present invention also relates to an abrasive sheet which provides for improved swarf clearance and reduction in quantities of diamond grit material used.
It has been a goal in the art to provide flexible abrasive sheets which have diamond-like hardness abrasive grit particles attached to discrete portions of the sheets. While many such constructions have been attempted in the past the resulting abrasive sheet materials were generally lacking in their durability in that particles were easily disattached during use, thereby rendering the abrasive sheet unsuitable for some uses. It has also been a goal to provide abrasive sheets which include discrete patterns or areas where abrasive grits are attached while leaving other areas open and without abrasive grits. It has also been a goal in the art to provide structures wherein portions of the abrasive grit particles remain exposed after formulation of the abrasive sheet to provide a biting or cutting type structure.
A flexible abrasive sheet is shown in U.S. Pat. No. 3,860,400 to Prowse et al. In this patent an abrasive sheet is disclosed wherein a perforated sheet material or mesh material is embedded in a non-conductive backing substrate such that portions of the sheet or mesh extend from the substrate. Thereafter the grit particles are electroplated onto the extending areas to provide the final abrasive grit structure. While this abrasive sheet provides an advantageous construction because the abrasive grit particles are attached by electroplating, the durability of the article is still limited as to an electroplated structure. Patents such as U.S. Pat. No. 4,047,902 to Wiand and U.S. Pat. No. 2,876,086 to Raymond disclose the use of masks or templates or the like to provide for discrete areas of diamond to attach to a substrate. While such structures have reduced diamond grit consumption, such procedures are not readily adaptable to braze techniques. Also, resulting structures have no provision for swarf removal or introduction of coolants or lubricants through the abrasive sheet as may be required in some applications.
It is therefore an object of the present invention to provide an abrasive sheet which is more durable than the prior constructions.
It is a further object of the present invention to provide a cutting type abrasive sheet.
It is still further an object of the present invention to provide improved methods of formulating abrasive sheets to produce an abrasive sheet in accordance with the above objects.
It is a further object of the present invention to provide a brazed abrasive sheet which allows for swarf removal and increase of coolants and lubricants and further is a brazed sheet with discrete areas of diamond for saving consumption of diamond in production of such a sheet.